Trump, 73, made an unannounced visit Saturday afternoon to the Walter Reed National Military Medical Center in Bethesda, Maryland.
A source with knowledge of the matter told CNN that Trump's trip to Walter Reed was not on his schedule as of Friday. The White House declined to comment on when the trip was scheduled.
"Anticipating a very busy 2020, the President is taking advantage of a free weekend here in Washington, D.C., to begin portions of his routine annual physical exam at Walter Reed," White House press secretary Stephanie Grisham said in a statement.
After a little more than two hours at Walter Reed, Trump returned to the White House.
Grisham said in a statement that the "President remains healthy and energetic without complaints," and that he met with the family of a US Special Forces soldier injured in Afghanistan.
"The President also stopped by to say hello to the medical staff of Walter Reed, to share his thanks for all the outstanding care they provide to our Wounded Warriors, and wish them an early happy Thanksgiving," Grisham added.
Grisham told CNN that the White House will not release results of the President's health until he completes all aspects of his annual physical.
Trump's trip to Walter Reed took place under unusual circumstances.
His two previous physical exams in office were announced ahead of time by the White House and noted on his daily public schedule.
This time, however, the President's motorcade drove to the medical center unannounced, with reporters under direction not to report his movement until they arrived at Walter Reed. Trump typically takes the Marine One helicopter to Walter Reed, but on Saturday's clear-skied day, the President opted for the motorcade.
CNN's Chief Medical Correspondent Sanjay Gupta said on CNN that there are many routine tests that can be done at the White House, but specific tests would require a visit to Walter Reed.
Gupta said the medical team at Walter Reed would typically "spend a lot of time" preparing for a presidential visit. It was unclear when the medical team at Walter Reed had received notice of the President's visit. CNN has reached out to Walter Reed for comment.
At February's physical exam, Trump weighed 243 pounds, four pounds more than the previous year's exam. His blood pressure was measured as 118/80, and results showed he had increased his daily dose of rosuvastatin, a medication used to treat high cholesterol, according to the exam results.
UPDATE: This is a developing story and is being updated.